/Engine/Plugins/Animation/ControlRig/Source/ControlRig/Public/Math/ControlRigMathLibrary.h
static void SolveBasicTwoBoneIK ( FTransform & BoneA, FTransform & BoneB, FTransform & Effector, const FVector & PoleVector, const FVector & PrimaryAxis, const FVector & SecondaryAxis, float SecondaryAxisWeight, float BoneALength, float BoneBLength, bool bEnableStretch, float StretchStartRatio, float StretchMaxRatio )